Pv. Bagger, DIRECT ESTIMATION OF VOLUMES IN OVARIAN FOLLICLES USING THE NUCLEATOR, APMIS. Acta pathologica, microbiologica et immunologica Scandinavica, 101(10), 1993, pp. 784-790
The aim of the study was to evaluate the precision of the nucleator pr
inciple with regard to estimation of follicle, oocyte and antral volum
es in individual follicles, as well as their average volumes in a grou
p of follicles. Nine isolated murine ovarian follicles embedded in pla
stic were orientated isotropically, cut into 20 Irm serial sections, a
nd stained with hematoxylin. In each follicle the volumes of the folli
cle, the antrum and the oocyte were estimated in two ways, both unbias
ed: Firstly, in just one unique section through the follicle, viz. the
section which contains the unique sampling point - the nucleolus of t
he oocyte - using the nucleator principle, and, secondly, in the compl
ete set of follicle sections using the Cavalieri principle. Estimates
using the Cavalieri, which are very precise (CE(Follicle)similar to 0.
03, CE(Oocyte)similar to 0.11, CE(Antrum)similar to 0.16), were interp
reted as the ''true'' values. Therefore, the precision (estimator vari
ation) of the nucleator estimates could be calculated. The nucleator e
stimates correlated well with the Cavalieri estimates: r(follicle)=0.9
5; r(antrum)=0.88; r(oocyte)=0.83. The nucleator provides very precise
estimates of the volumes of follicle, oocyte and antrum with a minima
l amount of effort, since the estimates are derived from measurements
in only four directions sampled in a uniform systematic way, the first
direction being chosen at random, in only one section through the fol
licle. Moreover, it is not necessary to know the precise thickness of
the section, and, finally, the estimates are expressed in correctly di
mensioned terms. The estimator variation of the nucleator (CE = 0.28)
is of minor importance compared to the biological variation (CV = 0.47
) in this realistic sample of follicles.